Jump to content

 
Photo

IKONOS data Geocoding/Orthorectification

- - - - -

  • Please log in to reply
5 replies to this topic

#1
himanshupahava

himanshupahava

    Newbie

  • New Member
  • Pip
  • 6 posts
  • India

hi,
I am having IKONOS MS and PAN data of some part of Hiamalyan region. I have to orthorectify this data. But i am not
having RPC files. When i am orthorectifying this data with respect to Survey of India maps and contour derived DEM, orthorectified data does not come good. It is having error in hundreds of meters.
FYI Survey of India maps follow Polychonic as a projection and Everest as spheroid and datum. N IKONOS orginal projection is UTM and Spheroid is WGS 84. This might be a problem, I dont know. This is only a guess.
If anybody is having idea how to orthorectify IKONOS data with respect to LOCAL projection and datum.???

#2
honeybee77

honeybee77

    Newbie

  • New Member
  • Pip
  • 8 posts
  • United States

hi,
I am having IKONOS MS and PAN data of some part of Hiamalyan region. I have to orthorectify this data. But i am not
having RPC files. When i am orthorectifying this data with respect to Survey of India maps and contour derived DEM, orthorectified data does not come good. It is having error in hundreds of meters.
FYI Survey of India maps follow Polychonic as a projection and Everest as spheroid and datum. N IKONOS orginal projection is UTM and Spheroid is WGS 84. This might be a problem, I dont know. This is only a guess.
If anybody is having idea how to orthorectify IKONOS data with respect to LOCAL projection and datum.???


Hi Himanshu,
What software program are you using for orthorectification? If it's ArcGIS, the help file implies it requires RPC data. In the past I have orthorectified sucessfully without RPC files using TNTmips. I believe I was able to specify an output projection/datum. We have the Pro version, but depending on your study area you may be able to get buy with a lower cost version. http://www.microimages.com/
Melisa

#3
honeybee77

honeybee77

    Newbie

  • New Member
  • Pip
  • 8 posts
  • United States

Sorry, I was wrong. I did not use TNTmips. I apologize for the mistake. I actually had to use PCI Geomatics for orthorectification and had to buy a special license. It was pricey as I recall. I'm not sure what other options are available for data without RPC files.

Melisa

#4
himanshupahava

himanshupahava

    Newbie

  • New Member
  • Pip
  • 6 posts
  • India

Sorry, I was wrong. I did not use TNTmips. I apologize for the mistake. I actually had to use PCI Geomatics for orthorectification and had to buy a special license. It was pricey as I recall. I'm not sure what other options are available for data without RPC files.

Melisa

Thanks Melisa,
Actually most of the software provides IKONOS orthorectication only with RPC files. If one is not having RPC file, he has to use classical orthorectification technique means with respect to Reference map/image n DEM.
But what i have observed for high resolution data(which are alredy in some projection for example UTM with WGS 84), it is not possible for me to correctly orthorectify data with respect to my projection(Polychonic with Everest).
I dont know what is the problem. Is it the native projection which data has or classic technique does not work for high resolution data.FYI my area of interset is Himalaya region. You know about the topography of this region.

Have a nice day.

Thanks & Regards
Himanshu

Edited by himanshupahava, 20 January 2010 - 02:23 AM.


#5
Nick H

Nick H

    Legendary Contributor

  • Validated Member
  • PipPipPipPipPip
  • 307 posts
  • Gender:Male
  • Location:Caversham, Reading, England.
  • United Kingdom

I don't think I'll be of much use to you, but out of interest, taking one of your Polyconic/Everest maps what does it say (if anything) in the margin about the Latitude and Longitude of origin and any false eastings and northings? Things like this.

Regards, N.
Caversham, Reading, England.

#6
honeybee77

honeybee77

    Newbie

  • New Member
  • Pip
  • 8 posts
  • United States

It is my understanding that once an image is orthorectified, it cannot be orthorectified again. Have you tried simply re-projecting it into your local projection?




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

-->